1. Field of the Invention
The present invention relates to an information record medium such as an optical disk of a high recording density type, which is capable of recording information such as video information, audio information and the like at a high density, and which is represented by a DVD (Digital Video or Versatile Disk). The present invention also relates to a recording apparatus for recording the information onto the information record medium, and a reproducing apparatus for reproducing the information from the information record medium.
2. Description of the Related Art
Conventionally, a so-called LD (Laser Disk) and a so-called CD (Compact Disk) are generalized as optical disks, on which information such as video information, audio information and the like is recorded.
On the LD, the CD or the like, the video information and the audio information are recorded together with time information indicating a time at which each information is to be reproduced with respect to a reproduction start position, which each LD or the like has, as a standard position. Thus, other than a general normal reproduction to reproduce the recorded information in the order of recording, various special reproductions are possible, such as a reproduction to extract and listen to an only desirable music out of a plurality of recorded musics, a reproduction to listen to the recorded musics in a random order and so on, in case of the CD, for example.
However, there is a problem that, according to the above mentioned CD, LD or the like, a so-called interactive and variegated reproduction is not possible in which the audience can have a plurality of selection branches as for the video or audio information to be displayed or sound-outputted and in which the audience can select them to watch or listen to it. Especially, it is not possible to perform such a complicated reproduction that the audience can select a desirable menu on a so-called GUI (Graphical User Interface) picture plane, in which a sub picture of a transparent user menu etc. is superimposed and displayed on a main picture.
On the other hand, various proposals and developments are being made as for the DVD, as an optical disk in which the memory capacity is improved by about ten times without changing the size of the optical disk itself as compared with the aforementioned conventional CD. According to the knowledge of the present inventors, it is anticipated that it is possible, as for the DVD having such a large memory capacity, to record the sub picture information in addition to the audio information and the video information, and constitute the aforementioned GUI picture plane which is obtained by reproducing the main and sub pictures; and further highlight-display one portion of the sub picture (e.g., display to emphasize one portion by changing the brightness and/or the chroma). Here, it is anticipated that a highlight-display of merely superimposing a static sub picture on a main picture can be realized rather easily by employing the conventional technique of superimposing the subtitles on a movie. On the other hand, in this kind of DVD of a large memory capacity type, it is anticipated that the aforementioned interactive reproduction can be performed.
However, if the highlight-displayed portion of the sub picture is tried to be moved at a high speed, it is anticipated that the time control with respect to the highlight-displayed portion of the sub picture, which is reproduced on the basis of a plurality of informations such as the main picture information (i.e. the video information), the sub picture information, the control information and so on, would be complicated and difficult. In addition, in order to perform the interactive reproduction on the display picture plane at the same function level as that of the personal computer, it is anticipated that the precise time management will be necessary for the highlight-displayed portion of the sub picture.
Further, in the technical art of the DVD, the actuality is such that a person having an ordinary skill in this art does not even recognize the subject itself to move the highlight-displayed portion of the sub picture at a high speed or to realize the interactive reproduction on the display picture plane at the same function level as that of the personal computer.